1. Field of the Invention
The present invention relates to an air conditioning system for a motor car.
2. Description of Related Art
Typically, automobiles are equipped with air conditioning systems for making drivers far more comfortable in hot or cold. Such an air conditioning system has air outlets disposed at a plurality of locations in the passenger compartment through which heated or cooled conditioning air blows into the passenger compartment. These air outlets, which are typically formed in the instrument panel located in front of the driver, include defroster air outlets through which conditioning air blows towards the front wind shield, side air outlets opening at opposite sides of the front of the instrument panel, a center air outlet opening at the center of the instrument panel and foot air outlet through which conditioning air blows towards feet of the driver. An air conditioning systems of this type such as described in, for example, Japanese Utility Patent Publication No. 5-408 has an air outlet opening in the ceiling of the passenger compartment. In this air conditioning system, conditioning air is introduced into a space between a sunroof and a sunshade which is formed with a plurality of openings as sunshade air outlets so that the conditioning air blows into the passenger compartment through the sunshade air outlets. This type of air conditioning system is enabled to blow conditioning air into the passenger compartment through a number of air outlets without complicating duct arrangement. There have been also proposed an air conditioning system which can discharge hot air out of the passenger compartment through a sunroof while the interior of the room temperature of the passenger compartment is high system as described in, for example, Japanese Unexamined Patent Publication No. 4-306120 and an air conditioning system which can blow conditioning air through air outlets in the instrument panel and a ceiling air outlet so as to eliminate a temperature difference of the room temperature from a selected temperature while the solar radiation intensity is high as described in, for example, Japanese Unexamined Patent Publication No. 9-220922.
In the prior art air conditioning system which controls air blow into the passenger compartment only through air outlets formed in the instrument panel and the ceiling of the compartment, there is such a fear that the passenger compartment is difficult to be kept far more comfortable. For example, although the passenger compartment is evenly cooled by causing conditioning air to blow from the ceiling of the passenger compartment with an effect of making the passengers comfortable while it is at a desired temperature setting, air conditioning rather gives uncomfortable feelings if conditioning air blows too much from the ceiling of the passenger compartment in the case where the passenger compartment is at a high temperature and is necessary to be rapidly cooled, in other words, where the outlet air temperature is controlled to be considerably lower than the room temperature. In such the case, cold wind blows against the neck of the passenger according to wind directions, which gives the passenger an uncomfortable feeling more strongly than a feeling of cool.